# Conferences and lectures

## Conferences and Lectures

75. *SV-rings*. Ord07 – Conference on Ordered Rings, Baton Rouge, Louisiana, USA, April 25 – 28, 2007

74. *Partially ordered rings as a tool in real algebraic geometry*. Colloquium Lecture, University of Ottawa, Ottawa, Canada, October 6, 2006.

73. *From rings of continuous functions to real closed rings*. McGill University, Montreal, Canada, October 3, 2006

72. *Convex extensions of rings of continuous functions*. Carthapos2006 – A Conference on Positivity Carthage, Tunisia, June 8 to June 10, 2006

71. *Convex subrings and convex extensions of partially ordered rings*. Conference "Real Algebra, Quadratic Forms and Model Theory; Algorithms and Applications", an activity of the "Trimester on Real geometry", Institut Henri Poincaré, Paris, France, November 2 to 9, 2005

70. *Real algebraic geometry and partially ordered rings*. Colloquium lecture, Banach Institute, Polish Academy of Sciences, and Politechnika Warszawska. Warszawa, Poland, October 6, 2005

69. *Convex Extensions of Partially Ordered Rings*. Lecture in the Algebra Seminar, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, February 7, 2005

68. *Convex Extensions of Partially Ordered Rings*. A series of lectures at the conference "Géométrie algébrique et analytique réelle". Kenitra, Morocco, September 13 to 20, 2004

67. *The semiring of sums of squares in a real field*. 7th Annual Conference in Ordered Algebraic Structures, University of Florida. Gainesville, Florida, USA, March 3 – March 6, 2004

66. *Semialgebraische Mengen und reelles Spektrum*. Festkolloquium zum 65. Geburtstag von Prof. Dr. Manfred Knebusch. Regensburg, Germany, February 14, 2004

65. *Positive Polynome*. Oberseminar "Reelle algebraische Geometrie". Regensburg, Germany, July 16, 2003

64. *Positive Polynomials on Semialgebraic Sets*. Lecture in the Special Session "Quantitative Results in Real Algebraic Geometry", First Joint Meeting RSME – AMS. Sevilla, Spain, June 18 – 21, 2003

63. *About Schmüdgen*. Lecture at the Miniconference "Real Algebraic Geometry", Universidad Complutense. Madrid, Spain, June 14 – 16, 2003

62. *Category-theoretic methods in semialgebraic geometry*. Seminar lecture, University of Bath. Bath, United Kingdom, February 11, 2003

61. *Semialgebraische Geometrie*. Lecture, Universität Konstanz. Konstanz, Germany, January 29, 2003

60. *Partially ordered rings*. Conference "Real Algebraic and Analytic Geometry – RAAG2002", First Annual Conference of the Network RAAG. Kazimierz Dolny, Poland, September 22 – 26, 2002

59. *Positive polynomials*. Seminar lecture, Université de Savoie. Chambery, France, June 28, 2002

58. *Positive polynomials in the plane*. Seminar lecture, Department of Mathematics, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 25, 2001

57. *Proconstructible subsets of real spectra*. Conference "Ordered Algebraic Structures", University of Florida. Gainesville, Florida, February 28 – March 3, 2001

56. *The role of partially ordered rings in real algebraic geometry*. Colloquium lecture, Department of Mathematics, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 22, 2000

55. *Real closed rings*. A series of seminar lectures, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 18 – 29, 2000

54. Rings of continuous functions and the real spectrum Conference on Ordered Algebraic Structures, Vanderbilt University Nashville, Tennessee, USA, March 9 - 11, 2000

53. *Real closed rings*. International Conference on Valuation Theory, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, July 28 - August 4, 1999

52. *Model theory of real closed rings*. Special session "Ordered Algebraic Structures", AMS Regional Conference. Gainesville, Florida, USA, March 12, 1999

51. *Real closed rings*. Algebra Seminar, Louisiana State University. Baton Rouge, Louisiana, USA, March 9, 1999

50. *Semi-algebraic geometry*. Colloquium lecture, Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, March 4, 1999

49. *Epimorphisms of partially ordered rings*. Conference RAAG1998. Levico Terme, Italy, September 20 - 25, 1998

48. *Real closed rings via reflections*. A series of lectures, Algebra seminar, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, March 5 - 7, 1998

47. *From rings of continuous functions to real closed rings*. Colloquium lecture, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, March 6, 1998

46. *Partially ordered rings of functions in real geometry*. Conference on "Ordered Algebraic Structures", University of Florida. Gainesville, Florida, USA, February 26 - 28, 1998

45. *A survey of spectral spaces*. HCM workshop on "Spectral Spaces in Real and p-adic Geometry", Universität Dortmund Dortmund, Germany, September 15 - 19, 1997

44. *Ringe von Funktionen in der reellen algebraischen Geometrie*. Oberseminar Priess, Mathematisches Institut der Universität München München, Germany, June 17, 1997

43. *Semi-algebraic functions*. Colloquium lecture, Departamento de Algebra, Facultad de Matemáticas, Universidad Complutense. Madrid, Spain, May 13, 1997

42. Categories of partially ordered rings Conference "Ordre en algèbre et logique, avec applications", CIRM, Luminy Marseille, France, April 21 - 25, 1997

41. *An introduction to real closed rings*. Seminar lecture, Universidad de Cantabria. Santander, Spain, October 28, 1996

40. *The semi-ring of sums of squares in a formally real field*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, June 25, 1996 38

39. *Real closed rings - examples and applications*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, June 24, 1996

38. *Epimorphisms of reduced partially ordered rings*. AMS Regional Conference, Lousiana State University. Baton Rouge, Louisiana, USA, April 19 - April 21, 1996

37. *Rings of continuous functions as real closed rings*. f-Ring Seminar, University of Florida. Gainesville, Florida, USA, February 1, 1996

36. *An introduction to real closed rings*. Special Semester in Real Algebraic Geometry and Ordered Structures, Louisiana State University. Baton Rouge, Louisiana, USA, January 18, 1996

35. *On epireflections of partially ordered rings* (jointly with J.J. Madden). Conference on Ordered Algebraic Structures. Curacao, Netherlands Antilles, June 26 - June 30, 1995

34. *Reflections on partially ordered rings*. Conference "Géométrie analytique et algébrique reelle", CIRM Luminy Marseille, France, September 12 - September 16, 1994

33. *Ringe semi-algebraischer Funktionen*. Colloquium lecture, Universität Regensburg. Regensburg, Germany, June 17, 1994

32. *Separating ideals*. Conference "Reelle algebraische Geometrie", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, May 1993

31. *Complete ideals*. Seminar lecture, Universit‚ de Rennes I. Rennes, France, December 3, 1992

30. Vollständige Ideale in Polynomringen Bayerisches Mathematisches Kolloquium Neuburg/Donau, Germany, May 28, 1992

29. *Piecewise polynomial functions*. Conference on Ordered Algebraic Structures, University of Florida. Gainesville, Florida, USA, December 12 - December 14, 1991

28. *Piecewise polynomial functions*. Algebra seminar, Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, December 10, 1991

27. *Simple ideals in polynomial rings with two variables*. Colloquium lecture. Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, December 9, 1991

26. *Sup-inf definierbare Funktionen*. Oberseminar Knebusch. Universität Regensburg, Regensburg, Germany, July 18, 1991 24

25. *Semi-algebraische Geometrie*. Kolloquium der Mathematischen Fakultät, Universität München. München, Germany, February 21, 1991

24. *Semi-algebraische Geometrie*. Mathematisches Institut der Universität Bern Bern, Switzerland, January 7, 1991

23. *Semi-algebraic Stiefel-Whitney classes*. Special Year in Real Algebraic Geometry and Quadratic Forms, University of California at Berkeley. Berkeley, California, USA, October 22, 1990

22. *Invertible ideals in real closed rings*. Conference "Real algebraic geometry", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, June 10 - June 16, 1990

21. *Algebraic topology of real closed spaces*. Conference "Real algebraic and analytic geometry", CIRM, Luminy Marseille, France, October 2 - October 6, 1989

20. *Witt rings of lattice-ordered groups*. Conference "Quadratische Formen", Mathematisches Forschungsinstitut Oberwolfach Oberwolfach, Germany, July 2 - July 8, 1989

19. Eine universelle Eigenschaft reell abgeschlossener Räume A series of lectures, Oberseminar Knebusch, Universität Regensburg Regensburg, Germany, November 1988 - January 1989 17

18. *Inverse real closed spaces*. Conference "Real Analytic and Algebraic Geometry". Trento, Italy, October 3 - October 7, 1988

17. * Reell abgeschlossene Räume*. Jahrestagung der DMV. Regensburg, Germany, September 19, 1988

16. *Lattice-ordered rings in semi-algebraic geometry*. Conference on Ordered Algebraic Structures. Curacao, Netherlands Antilles, August 9 - August 13, 1988

15. Gröbner-Basen Mathematisches Kolloquium, Universität Konstanz. Konstanz, Germany, January 22, 1988

14. *Kompaktifizierung von Varietäten*. A series of lectures, Oberseminar Knebusch, Universität Regensburg. Regensburg, Germany, May 13 - May 15, 1987

13. *Standardbasen*. Fachbereich Mathematik und Informatik, Universität Passau. Passau, Germany, November 14, 1986

12. *Witt rings of higher level*. Conference "Quadratic Forms and Real Algebraic Geometry", Oregon State University. Corvallis, Oregon, USA, July 24 - July 30, 1986

11. *Real closures of fields with higher level orderings*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, November 26, 1985 9

10. *Open semi-algebraic mappings*. Conference "Géométrie algébrique reelle", CIRM, Luminy. Marseille, France, September 16 - September 20, 1985

9. *The real spectrum in semi-algebraic geometry*. Seminar on Real Algebraic Geometry, Université de Rennes I. Rennes, France, November 21, 1985

8. *Open semi-algebraic mappings*. Conference "Géométrie algébrique reelle", CIRM Luminy. Marseille, France, September 16 - September 20, 1985

7. *Reell abgeschlossene Ringe*. A series of lectures, Oberseminar Knebusch, Universität Regensburg. Regensburg, Germany, Luly 4 - July 23, 1985

6. *Chain signatures and Witt rings of higher level*. Conference "Quadratische Formen", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, June 2 - June 8, 1985

5. *Real closed spaces*. Conference "Reelle algebraische Geometrie". Oberwolfach, Germany, September 2 - September 8, 1984

4. *Semi-algebraic spaces*. First International Symposium on Ordered Algebraic Structures, CIRM, Luminy. Marseille, France, June 11 - June 16, 1984

3. *Semi-algebraische Geometrie*. Mathematisches Kolloquium, Universität Regensburg. Regensburg, Germany, November 4, 1983

2. Real closed spaces Conference on Ordered Fields and Real Algebraic Geometry. Boulder, Colorado, USA, July 1983

1. *The strong topology on real algebraic varieties*. 87th Annual Meeting of the AMS. San Francisco, California, USA, January 7 - January 11, 1981

## [Translate to english:] Tagungen und Vorträge (Kopie 1)

[Translate to english:]

# Scientific Lectures

75. *SV-rings*. Ord07 – Conference on Ordered Rings, Baton Rouge, Louisiana, USA, April 25 – 28, 2007

74. *Partially ordered rings as a tool in real algebraic geometry*. Colloquium Lecture, University of Ottawa, Ottawa, Canada, October 6, 2006.

73. *From rings of continuous functions to real closed rings*. McGill University, Montreal, Canada, October 3, 2006

72. *Convex extensions of rings of continuous functions*. Carthapos2006 – A Conference on Positivity Carthage, Tunisia, June 8 to June 10, 2006

71. *Convex subrings and convex extensions of partially ordered rings*. Conference "Real Algebra, Quadratic Forms and Model Theory; Algorithms and Applications", an activity of the "Trimester on Real geometry", Institut Henri Poincaré, Paris, France, November 2 to 9, 2005

70. *Real algebraic geometry and partially ordered rings*. Colloquium lecture, Banach Institute, Polish Academy of Sciences, and Politechnika Warszawska. Warszawa, Poland, October 6, 2005

69. *Convex Extensions of Partially Ordered Rings*. Lecture in the Algebra Seminar, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, February 7, 2005

68. *Convex Extensions of Partially Ordered Rings*. A series of lectures at the conference "Géométrie algébrique et analytique réelle". Kenitra, Morocco, September 13 to 20, 2004

67. *The semiring of sums of squares in a real field*. 7th Annual Conference in Ordered Algebraic Structures, University of Florida. Gainesville, Florida, USA, March 3 – March 6, 2004

66. *Semialgebraische Mengen und reelles Spektrum*. Festkolloquium zum 65. Geburtstag von Prof. Dr. Manfred Knebusch. Regensburg, Germany, February 14, 2004

65. *Positive Polynome*. Oberseminar "Reelle algebraische Geometrie". Regensburg, Germany, July 16, 2003

64. *Positive Polynomials on Semialgebraic Sets*. Lecture in the Special Session "Quantitative Results in Real Algebraic Geometry", First Joint Meeting RSME – AMS. Sevilla, Spain, June 18 – 21, 2003

63. *About Schmüdgen*. Lecture at the Miniconference "Real Algebraic Geometry", Universidad Complutense. Madrid, Spain, June 14 – 16, 2003

62. *Category-theoretic methods in semialgebraic geometry*. Seminar lecture, University of Bath. Bath, United Kingdom, February 11, 2003

61. *Semialgebraische Geometrie*. Lecture, Universität Konstanz. Konstanz, Germany, January 29, 2003

60. *Partially ordered rings*. Conference "Real Algebraic and Analytic Geometry – RAAG2002", First Annual Conference of the Network RAAG. Kazimierz Dolny, Poland, September 22 – 26, 2002

59. *Positive polynomials*. Seminar lecture, Université de Savoie. Chambery, France, June 28, 2002

58. *Positive polynomials in the plane*. Seminar lecture, Department of Mathematics, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 25, 2001

57. *Proconstructible subsets of real spectra*. Conference "Ordered Algebraic Structures", University of Florida. Gainesville, Florida, February 28 – March 3, 2001

56. *The role of partially ordered rings in real algebraic geometry*. Colloquium lecture, Department of Mathematics, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 22, 2000

55. *Real closed rings*. A series of seminar lectures, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, September 18 – 29, 2000

54. Rings of continuous functions and the real spectrum Conference on Ordered Algebraic Structures, Vanderbilt University Nashville, Tennessee, USA, March 9 - 11, 2000

53. *Real closed rings*. International Conference on Valuation Theory, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, July 28 - August 4, 1999

52. *Model theory of real closed rings*. Special session "Ordered Algebraic Structures", AMS Regional Conference. Gainesville, Florida, USA, March 12, 1999

51. *Real closed rings*. Algebra Seminar, Louisiana State University. Baton Rouge, Louisiana, USA, March 9, 1999

50. *Semi-algebraic geometry*. Colloquium lecture, Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, March 4, 1999

49. *Epimorphisms of partially ordered rings*. Conference RAAG1998. Levico Terme, Italy, September 20 - 25, 1998

48. *Real closed rings via reflections*. A series of lectures, Algebra seminar, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, March 5 - 7, 1998

47. *From rings of continuous functions to real closed rings*. Colloquium lecture, University of Saskatchewan. Saskatoon, Saskatchewan, Canada, March 6, 1998

46. *Partially ordered rings of functions in real geometry*. Conference on "Ordered Algebraic Structures", University of Florida. Gainesville, Florida, USA, February 26 - 28, 1998

45. *A survey of spectral spaces*. HCM workshop on "Spectral Spaces in Real and p-adic Geometry", Universität Dortmund Dortmund, Germany, September 15 - 19, 1997

44. *Ringe von Funktionen in der reellen algebraischen Geometrie*. Oberseminar Priess, Mathematisches Institut der Universität München München, Germany, June 17, 1997

43. *Semi-algebraic functions*. Colloquium lecture, Departamento de Algebra, Facultad de Matemáticas, Universidad Complutense. Madrid, Spain, May 13, 1997

42. Categories of partially ordered rings Conference "Ordre en algèbre et logique, avec applications", CIRM, Luminy Marseille, France, April 21 - 25, 1997

41. *An introduction to real closed rings*. Seminar lecture, Universidad de Cantabria. Santander, Spain, October 28, 1996

40. *The semi-ring of sums of squares in a formally real field*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, June 25, 1996 38

39. *Real closed rings - examples and applications*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, June 24, 1996

38. *Epimorphisms of reduced partially ordered rings*. AMS Regional Conference, Lousiana State University. Baton Rouge, Louisiana, USA, April 19 - April 21, 1996

37. *Rings of continuous functions as real closed rings*. f-Ring Seminar, University of Florida. Gainesville, Florida, USA, February 1, 1996

36. *An introduction to real closed rings*. Special Semester in Real Algebraic Geometry and Ordered Structures, Louisiana State University. Baton Rouge, Louisiana, USA, January 18, 1996

35. *On epireflections of partially ordered rings* (jointly with J.J. Madden). Conference on Ordered Algebraic Structures. Curacao, Netherlands Antilles, June 26 - June 30, 1995

34. *Reflections on partially ordered rings*. Conference "Géométrie analytique et algébrique reelle", CIRM Luminy Marseille, France, September 12 - September 16, 1994

33. *Ringe semi-algebraischer Funktionen*. Colloquium lecture, Universität Regensburg. Regensburg, Germany, June 17, 1994

32. *Separating ideals*. Conference "Reelle algebraische Geometrie", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, May 1993

31. *Complete ideals*. Seminar lecture, Universit‚ de Rennes I. Rennes, France, December 3, 1992

30. Vollständige Ideale in Polynomringen Bayerisches Mathematisches Kolloquium Neuburg/Donau, Germany, May 28, 1992

29. *Piecewise polynomial functions*. Conference on Ordered Algebraic Structures, University of Florida. Gainesville, Florida, USA, December 12 - December 14, 1991

28. *Piecewise polynomial functions*. Algebra seminar, Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, December 10, 1991

27. *Simple ideals in polynomial rings with two variables*. Colloquium lecture. Department of Mathematics, Louisiana State University. Baton Rouge, Louisiana, USA, December 9, 1991

26. *Sup-inf definierbare Funktionen*. Oberseminar Knebusch. Universität Regensburg, Regensburg, Germany, July 18, 1991 24

25. *Semi-algebraische Geometrie*. Kolloquium der Mathematischen Fakultät, Universität München. München, Germany, February 21, 1991

24. *Semi-algebraische Geometrie*. Mathematisches Institut der Universität Bern Bern, Switzerland, January 7, 1991

23. *Semi-algebraic Stiefel-Whitney classes*. Special Year in Real Algebraic Geometry and Quadratic Forms, University of California at Berkeley. Berkeley, California, USA, October 22, 1990

22. *Invertible ideals in real closed rings*. Conference "Real algebraic geometry", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, June 10 - June 16, 1990

21. *Algebraic topology of real closed spaces*. Conference "Real algebraic and analytic geometry", CIRM, Luminy Marseille, France, October 2 - October 6, 1989

20. *Witt rings of lattice-ordered groups*. Conference "Quadratische Formen", Mathematisches Forschungsinstitut Oberwolfach Oberwolfach, Germany, July 2 - July 8, 1989

19. Eine universelle Eigenschaft reell abgeschlossener Räume A series of lectures, Oberseminar Knebusch, Universität Regensburg Regensburg, Germany, November 1988 - January 1989 17

18. *Inverse real closed spaces*. Conference "Real Analytic and Algebraic Geometry". Trento, Italy, October 3 - October 7, 1988

17. * Reell abgeschlossene Räume*. Jahrestagung der DMV. Regensburg, Germany, September 19, 1988

16. *Lattice-ordered rings in semi-algebraic geometry*. Conference on Ordered Algebraic Structures. Curacao, Netherlands Antilles, August 9 - August 13, 1988

15. Gröbner-Basen Mathematisches Kolloquium, Universität Konstanz. Konstanz, Germany, January 22, 1988

14. *Kompaktifizierung von Varietäten*. A series of lectures, Oberseminar Knebusch, Universität Regensburg. Regensburg, Germany, May 13 - May 15, 1987

13. *Standardbasen*. Fachbereich Mathematik und Informatik, Universität Passau. Passau, Germany, November 14, 1986

12. *Witt rings of higher level*. Conference "Quadratic Forms and Real Algebraic Geometry", Oregon State University. Corvallis, Oregon, USA, July 24 - July 30, 1986

11. *Real closures of fields with higher level orderings*. Seminar on Ordered Algebraic Structures (Delon - Dickmann - Gondard). Université‚ Paris VII Paris, France, November 26, 1985 9

10. *Open semi-algebraic mappings*. Conference "Géométrie algébrique reelle", CIRM, Luminy. Marseille, France, September 16 - September 20, 1985

9. *The real spectrum in semi-algebraic geometry*. Seminar on Real Algebraic Geometry, Université de Rennes I. Rennes, France, November 21, 1985

8. *Open semi-algebraic mappings*. Conference "Géométrie algébrique reelle", CIRM Luminy. Marseille, France, September 16 - September 20, 1985

7. *Reell abgeschlossene Ringe*. A series of lectures, Oberseminar Knebusch, Universität Regensburg. Regensburg, Germany, Luly 4 - July 23, 1985

6. *Chain signatures and Witt rings of higher level*. Conference "Quadratische Formen", Mathematisches Forschungsinstitut Oberwolfach. Oberwolfach, Germany, June 2 - June 8, 1985

5. *Real closed spaces*. Conference "Reelle algebraische Geometrie". Oberwolfach, Germany, September 2 - September 8, 1984

4. *Semi-algebraic spaces*. First International Symposium on Ordered Algebraic Structures, CIRM, Luminy. Marseille, France, June 11 - June 16, 1984

3. *Semi-algebraische Geometrie*. Mathematisches Kolloquium, Universität Regensburg. Regensburg, Germany, November 4, 1983

2. Real closed spaces Conference on Ordered Fields and Real Algebraic Geometry. Boulder, Colorado, USA, July 1983

1. *The strong topology on real algebraic varieties*. 87th Annual Meeting of the AMS. San Francisco, California, USA, January 7 - January 11, 1981